Details for: CL0000158

Cell ID: CL0000158

Cell Name: club cell

Description: A non-mucous, epithelial secretory cell that is part of the tracheobronchial tree. A club cell has short microvilli but no cilia. A club cell is able to multiply and differentiate into ciliated cells to regenerate the bronchiolar epithelium and it also protects the tracheobronchial epithelium.

Synonyms: Clara cell

Selected Context(s): Overall

Gene Significance Landscape

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Genes

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Cell Significance Index (CSI) is uniquely calculated to reveal cell-specific gene markers. More info here

Significant Genes List

Genes with the highest and lowest Percentile Rank Scores (PRS) for club cell within the selected context(s).

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for club cell. Higher scores indicate a stronger, more significant difference in expression.
(Previously described as "Fold Change", but now represents Cliff's Delta × –log10(p).)

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for club cell. Higher scores indicate a stronger, more significant difference in expression.
Average CSI: csi sum / gene count
Cell network configuration

This network visualizes key genes for club cell. It primarily includes:
1. Top genes highly significant for this cell (Num. Top Cell Genes - based on the 'Min. CSI' setting).
2. Any additional specific 'Context Genes' you add below.
The final network is a combined view. Choose an Interaction Source (pathways or protein interactions) and optionally compare CSI scores with a Baseline Cell Type.

Maximum number of selected genes.
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Select a context for the target cell.
Target Cell for CSI:  club cell (CL0000158)

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Nodes (Genes):
 Query Gene
Node size also reflects Target Cell CSI magnitude.
Node Color (Target Cell CSI in specific network):
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 High
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 Very Low
 N/A or Not Sig.
Edges (Interactions):
 STRING (Protein-Protein)
 ONTOLOGY (Shared Pathway)
 Colors vary by pathway category; default arrow applies.

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## Summary The [club cell](/details-cell/CL0000158), also known as a Clara cell, is a non-ciliated, secretory epithelial cell found in the tracheobronchial tree. Its primary functions include protecting the bronchiolar epithelium, detoxifying harmful substances, and acting as a progenitor cell to regenerate the epithelium by differentiating into [ciliated cells](/details-cell/CL0000066). The gene significance profile for the [club cell](/details-cell/CL0000158) is overwhelmingly dominated by genes involved in mitochondrial energy production and oxidative stress management. The high expression specificity of numerous components of the electron transport chain, such as [COX1](/details-gene/4512) (CSI-Z: 61.69) and [CYTB](/details-gene/4519) (CSI-Z: 57.64), alongside detoxification enzymes like [GSTP1](/details-gene/2950) (CSI-Z: 59.13), suggests that this cell type is defined by an exceptionally high metabolic rate, likely dedicated to its critical protective and secretory functions within the lung airway. ## Key Characteristics and Function The molecular signature of the [club cell](/details-cell/CL0000158) points towards a highly specialized role as a metabolic and protective hub in the airway epithelium. The top marker genes can be organized into several key functional clusters. * **High Metabolic Activity and Mitochondrial Respiration:** The most striking feature is the significant enrichment of genes encoding components of the mitochondrial electron transport chain. These include multiple mitochondrially-encoded genes such as [COX1](/details-gene/4512), [CYTB](/details-gene/4519), [ND1](/details-gene/4535), [ND2](/details-gene/4536), [ND4](/details-gene/4538), and [COX2](/details-gene/4513), as well as nuclear-encoded mitochondrial proteins like [ATP5MC2](/details-gene/517) and [COX7C](/details-gene/1350). The high specificity (CSI Z-scores) of these genes indicates that this intense level of aerobic respiration is a defining characteristic of [club cells](/details-cell/CL0000158) compared to other cells in their environment. This high energy output is likely required to fuel their extensive secretory and detoxification activities. * **Detoxification and Xenobiotic Metabolism:** The high significance of [GSTP1](/details-gene/2950), a glutathione S-transferase, underscores the cell's crucial role in detoxifying inhaled pollutants and reactive oxygen species. This is complemented by [SAT1](/details-gene/6303), an enzyme involved in polyamine catabolism, which is often upregulated in response to cellular stress and is essential for regulating cell growth and differentiation. * **Oxidative Stress Management and Iron Homeostasis:** The significant expression of both ferritin heavy and light chains, [FTH1](/details-gene/2495) and [FTL](/details-gene/2512), highlights a specialized function in sequestering intracellular iron. This is a critical protective mechanism to prevent iron-catalyzed oxidative damage (via the Fenton reaction) at the air-liquid interface, a site of high oxidative potential. * **Protein Synthesis and Secretion:** As expected for a secretory cell, genes associated with high translational activity are prominent. These include [TPT1](/details-gene/7178) (Translationally Controlled Tumor Protein) and [PABPC1](/details-gene/26986) (Poly(A)-Binding Protein Cytoplasmic 1), which are fundamental to protein synthesis and mRNA stability. This supports their role in producing and secreting components of the airway lining fluid. * **Calcium Signaling and Cellular Structure:** The presence of [S100A6](/details-gene/6277), a calcium-binding protein, and myosin light chains ([MYL12B](/details-gene/103910), [MYL6](/details-gene/4637)) suggests that calcium-mediated signaling and cytoskeletal dynamics are important for cellular processes, which may include vesicle trafficking for secretion and maintaining cell morphology. **Overall**, the gene profile depicts a cell that is a highly active metabolic engine, specialized for secretion and the detoxification of the airway environment, thereby playing a central role in epithelial protection and homeostasis. ## Clinical Significance and Contextual Roles Given their strategic location and protective functions, dysfunction of [club cells](/details-cell/CL0000158) is implicated in numerous respiratory diseases. The high expression of detoxification enzymes like [GSTP1](/details-gene/2950) positions the [club cell](/details-cell/CL0000158) as a first line of defense against inhaled toxins, smoke, and pollutants. A decrease in their number or function could contribute to the pathogenesis of conditions like Chronic Obstructive Pulmonary Disease (COPD) and asthma. Furthermore, their role as progenitors means that damage to the [club cell](/details-cell/CL0000158) population can impair epithelial repair following injury, leading to chronic inflammation and tissue remodeling. The profound reliance on mitochondrial respiration suggests that these cells may be particularly vulnerable to mitochondrial dysfunction. Pathologies associated with mitochondrial defects or chronic metabolic stress could disproportionately affect [club cells](/details-cell/CL0000158), leading to a compromised epithelial barrier. The identification of [ITM2B](/details-gene/9445) as a significant marker is intriguing. While mutations in this gene are known to cause familial British and Danish dementias through the formation of amyloid peptides ([Link](https://doi.org/10.1038/21637), [Link](https://doi.org/10.1073/pnas.080076097)), its specific role in lung physiology is not well-defined. Its expression in [club cells](/details-cell/CL0000158) may point to uncharacterized functions in protein processing or secretion that could be relevant in lung proteinopathies like pulmonary fibrosis. Similarly, [TMBIM6](/details-gene/7009), a protein known to regulate calcium homeostasis and suppress apoptosis, may be critical for club cell survival under conditions of high oxidative or xenobiotic stress. ## Potential Mechanisms and Research Directions 1. **Hypothesis: Club cells function as a high-energy metabolic shield, coupling massive mitochondrial output to the detoxification of inhaled xenobiotics.** The data suggest that the defining feature of [club cells](/details-cell/CL0000158) is not just detoxification, but the immense energetic capacity that supports it. This bioenergetic specialization may be a key determinant of airway health and susceptibility to inhaled pollutants. * **Surprising Findings:** The sheer number of distinct mitochondrial electron transport chain subunits ([COX1](/details-gene/4512), [COX2](/details-gene/4513), [CYTB](/details-gene/4519), [ND1](/details-gene/4535), [ND2](/details-gene/4536), [ND4](/details-gene/4538)) appearing as top *specificity* markers is remarkable. This implies that the entire respiratory apparatus is uniquely upregulated in these cells compared to their neighbors, suggesting a constitutively active state of oxidative phosphorylation that is central to their identity. * **Testable Questions:** Does exposure to common air pollutants (e.g., ozone or particulate matter) in an air-liquid interface co-culture model induce mitochondrial stress specifically in [club cells](/details-cell/CL0000158)? Furthermore, would pharmacologic inhibition of cytochrome c oxidase impair the ability of these cells to metabolize compounds detoxified by Cytochrome P450 enzymes, which are known to be abundant in [club cells](/details-cell/CL0000158)? 2. **Hypothesis: Club cells actively manage the airway microenvironment's iron and redox balance to prevent oxidative damage and regulate inflammation.** The co-enrichment of genes for iron sequestration ([FTH1](/details-gene/2495), [FTL](/details-gene/2512]) and glutathione metabolism ([GSTP1](/details-gene/2950]) points to a coordinated system for controlling oxidative stress. This function is likely critical for preventing damage to the delicate alveolar structures and for modulating local immune responses. * **Surprising Findings:** The high significance of [TMBIM6](/details-gene/7009), a Ca2+/H+ exchanger with anti-apoptotic properties, is unexpected in this context. Its role may be to protect the cell from apoptosis induced by the high levels of oxidative stress and calcium signaling inherent to its function, thus ensuring the stability of the protective epithelial layer. * **Testable Questions:** In mouse models of inflammatory lung disease, such as asthma or viral infection, is the expression of [FTH1](/details-gene/2495) and [GSTP1](/details-gene/2950) in [club cells](/details-cell/CL0000158) altered? Does conditional knockout of ferritin in [club cells](/details-cell/CL0000158) lead to increased markers of lipid peroxidation and heightened inflammatory cell infiltration in the bronchiolar lavage fluid following an oxidative challenge?